Ion Mobility Spectrometer Pressure Gradient Design
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Solution Overview
Problem
Existing ion mobility spectrometers face low sample injection efficiency due to limited negative pressure effect and high temperature issues with micro-pumps, leading to performance degradation and reduced service life.
Innovation Solution
The ion mobility spectrometer design includes air inlets with a needle valve and filtering devices to control air flow speed, a micropore structure separating the drift and ionization regions, and a focusing electrode to enhance ionization and storage, while using metal meshed sheets to clamp the semipermeable membrane, creating a controllable low air pressure for improved permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a micro-pump is coupled in series between the semipermeable membrane and the ionization region to form negative pressure, then the permeation rate of the semipermeable membrane is increased, but the micro-pump cannot run continuously and steadily at high temperature (above 100 degrees), limiting the application and service life of the IMS
Solution Approach 1:
The patent removes the micro-pump from the high-temperature zone by extracting it from the system between the semipermeable membrane and ionization region. Instead, a natural pressure difference is created through the temperature gradient itself, with the hot end (ionization region) having lower pressure and the cold end (sample injection region) having higher pressure, eliminating the need for a micro-pump that would fail at high temperatures.
Solution Approach 2:
The mechanical micro-pump system is replaced with a thermal-driven pressure gradient system. The temperature difference between the hot and cold ends naturally creates the pressure difference needed for sample transport, substituting mechanical pumping with thermal convection and pressure gradient-driven flow.
2Productivity
If the interior structure of the micro-pump is exposed to high temperature and sample substances, then it is easily polluted and difficult to clean, resulting in performance degradation of the IMS
Solution Approach 1:
The micro-pump is completely extracted from the high-temperature sample path. The patent uses a pumpless design where sample transport is achieved through natural pressure gradients created by temperature differences, eliminating the component that would otherwise be polluted and difficult to clean.
Solution Approach 2:
The patent creates different thermal environments in different regions: the sample injection region remains at lower temperature while the ionization region is heated. This local temperature differentiation drives sample flow without requiring a micro-pump in the hot zone, keeping critical components away from contaminating conditions.
3Object-affected harmful factors
If a semipermeable membrane is employed with negative pressure formed by air flow speeds on both sides, then the environment cleanliness level required by the IMS is lowered, but the sample injection efficiency remains low
Solution Approach 1:
The patent changes the pressure parameter distribution by creating a temperature-driven pressure gradient instead of relying on equal and opposite air flows. The hot end naturally has lower pressure and the cold end has higher pressure, creating unidirectional sample flow through the membrane with improved injection efficiency while maintaining cleanliness benefits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly increases sample injection efficiency, reduces the sealing requirements, and prevents semipermeable membrane protrusion, maintaining ion storage levels and extending the device's operational life.
Implementation Method 1
designing and adjusting appropriate air flow speeds on both sides of the semipermeable membrane, however, the effect of the negative pressure is limited to a certain degree
Implementation Method 2
a semipermeable membrane is employed so that it makes the environment cleanliness level required by the IMS lower
Implementation Method 3
an ionization section... identifies ions based on different drifting speeds of different ions in a uniform weak electric field
Implementation Method 4
The ion mobility spectrometer (IMS) effect identifies ions based on different drifting speeds of different ions in a uniform weak electric field
Implementation Method 5
an air outlet connected with an air extracting pump for extracting air is arranged in the ionization region adjacent to the terminal electrode
Data Source
AI summary
Disclosed is an ion mobility spectrometer. The ion mobility spectrometer comprises a sample injector (14), a semipermeable membrane (15), an ionization region (16), a terminal electrode (18), an ion storage region, a drift region and a Faraday plate (22), which are arranged along a drift tube in turn, wherein one or more air inlets (29) connected with a needle valve (30) and a first filtering device (31) are arranged in one side near the semipermeable membrane (15) of the ionization region (16), there is at least one opening in the terminal electrode (18), whose diameter is smaller than the diameter of the air inlets (29), an air outlet (28) connected with an air extracting pump (27) is arranged near the terminal electrode (18) in the ionization region (16), the drift region is separated from the ionization region (16) by a micropore structure of the ion storage region, another air outlet (25) connected with another air extracting pump (26) is arranged at one side near the Faraday plate (22) of the terminal electrode (18).